package org.ithink.util.io;

import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.zip.Deflater;
import java.util.zip.DeflaterOutputStream;
import java.util.zip.Inflater;
import java.util.zip.InflaterInputStream;

/**
 * ZLib压缩工具
 * 
 * @author <a href="mailto:zlex.dongliang@gmail.com">梁栋</a>
 * @version 1.0
 * @since 1.0
 */
public class ZLibUtil {

  /**
   * 压缩
   * 
   * @param data
   *            待压缩数据
   * @return byte[] 压缩后的数据
   */
  public static byte[] compress(byte[] data) {
    byte[] output = new byte[0];

    Deflater compresser = new Deflater();

    compresser.reset();
    compresser.setInput(data);
    compresser.finish();
    ByteArrayOutputStream bos = new ByteArrayOutputStream(data.length);
    try {
      byte[] buf = new byte[1024];
      while (!compresser.finished()) {
        int i = compresser.deflate(buf);
        bos.write(buf, 0, i);
      }
      output = bos.toByteArray();
    } catch (Exception e) {
      output = data;
      e.printStackTrace();
    } finally {
      try {
        bos.close();
      } catch (IOException e) {
        e.printStackTrace();
      }
    }
    compresser.end();
    return output;
  }

  /**
   * 压缩
   * 
   * @param data
   *            待压缩数据
   * 
   * @param os
   *            输出流
   */
  public static void compress(byte[] data, OutputStream os) {
    DeflaterOutputStream dos = new DeflaterOutputStream(os);

    try {
      dos.write(data, 0, data.length);

      dos.finish();

      dos.flush();
    } catch (IOException e) {
      e.printStackTrace();
    }
  }

  /**
   * 解压缩
   * 
   * @param data
   *            待压缩的数据
   * @return byte[] 解压缩后的数据
   */
  public static byte[] decompress(byte[] data) {
    byte[] output = new byte[0];

    Inflater decompresser = new Inflater();
    decompresser.reset();
    decompresser.setInput(data);

    ByteArrayOutputStream o = new ByteArrayOutputStream(data.length);
    try {
      byte[] buf = new byte[1024];
      while (!decompresser.finished()) {
        int i = decompresser.inflate(buf);
        o.write(buf, 0, i);
      }
      output = o.toByteArray();
    } catch (Exception e) {
      output = data;
      e.printStackTrace();
    } finally {
      try {
        o.close();
      } catch (IOException e) {
        e.printStackTrace();
      }
    }

    decompresser.end();
    return output;
  }

  /**
   * 解压缩
   * 
   * @param is
   *            输入流
   * @return byte[] 解压缩后的数据
   */
  public static byte[] decompress(InputStream is) {
    InflaterInputStream iis = new InflaterInputStream(is);
    ByteArrayOutputStream o = new ByteArrayOutputStream(1024);
    try {
      int i = 1024;
      byte[] buf = new byte[i];

      while ((i = iis.read(buf, 0, i)) > 0) {
        o.write(buf, 0, i);
      }

    } catch (IOException e) {
      e.printStackTrace();
    }
    return o.toByteArray();
  }
  
  public static void main(String[] args) {
    ZLibUtil util = new ZLibUtil();
    util.testBytes();
    util.testFile();
  }
  
  public final void testBytes() {
    System.err.println("字节压缩／解压缩测试");
    String inputStr = "snowolf@zlex.org;dongliang@zlex.org;zlex.dongliang@zlex.org";
    System.err.println("输入字符串:\t" + inputStr);
    byte[] input = inputStr.getBytes();
    System.err.println("输入字节长度:\t" + input.length);

    byte[] data = ZLibUtil.compress(input);
    System.err.println("压缩后字节长度:\t" + data.length);

    byte[] output = ZLibUtil.decompress(data);
    System.err.println("解压缩后字节长度:\t" + output.length);
    String outputStr = new String(output);
    System.err.println("输出字符串:\t" + outputStr);

  }

  public final void testFile() {
    String filename = "zlib";
    File file = new File(filename);
    System.err.println("文件压缩／解压缩测试");
    String inputStr = "snowolf@zlex.org;dongliang@zlex.org;zlex.dongliang@zlex.org";
    System.err.println("输入字符串:\t" + inputStr);
    byte[] input = inputStr.getBytes();
    System.err.println("输入字节长度:\t" + input.length);

    try {

      FileOutputStream fos = new FileOutputStream(file);
      ZLibUtil.compress(input, fos);
      fos.close();
      System.err.println("压缩后字节长度:\t" + file.length());
    } catch (Exception e) {
    }

    byte[] output = null;

    try {
      FileInputStream fis = new FileInputStream(file);
      output = ZLibUtil.decompress(fis);
      fis.close();

    } catch (Exception e) {
    }
    System.err.println("解压缩后字节长度:\t" + output.length);
    String outputStr = new String(output);
    System.err.println("输出字符串:\t" + outputStr);

  }
}

